Psychopathy is a special interest of mine
Sine anti social personality disorder develops from environmental issues and isn't neurological in origin, it is different from psychopathy. MRI scans show that psychopaths brains are wired differently, much in the same way autistics' brains are wired differently.
I have thought too that psychopathy and autism are opposites. As a previous poster stated, manipulation and charm are skills of the psychopath that are oh so absent in aspires (usually). When you look at the traits of psychopathy on Dr Hare's PCLR, they tend to require skills typically absent in autistics so I have often thought that you wouldn't find clinical psychopathy (someone with a score of more than 30 on the PCLR) co-morbid with autism.
I am fascinated by the overlaps between autism and psychopathy ... There seems to be a disconnect from emotion, a flat affect and difficulties with empathy - though this latter one is caused by different reasons.
By the way, there's a heck of a lot of crap out there about psychopathy, even from people who ought to be in a position to know better. Some reliable experts I've discovered are Dr Robert Hare, kent Kiehl, Mary ellen o'toole and jim fallon.
Psychopath's often can understand empathy, but they don't feel it like we do. For Autistic individuals, they can feel it, but they often have issues with understanding it (so I guess that this one could be deemed as an opposite). I also have found that Psychopaths can be more emotional, but in more of a way that the vast majority of us would perceive as being a negative thing. Anyhow, I wouldn't define them as being opposites. Not all are 'forthright', and some are fully capable of manipulating (or committing crimes).